Shipping is a large sector of the transportation industry, rivaling aviation in size, and it is a major carbon emitter. Three percent of carbon emissions come from the maritime industry. The ship categories producing the most emissions are bulk carriers, tankers and container ships. The industry faces an imperative need for decarbonization. The current trajectory leads to a 20% increase in emissions. Although shipping is a carbon-efficient mode of transportation, it currently doesn’t get any passes and needs to do its part in reducing man-made emissions.
To be in line with the well-known scenarios of the International Energy Agency, the so-called scenario of warming well below two degrees, or warming of 1.5 degrees, significant decarbonization would be necessary, and this is not not yet.
Shipping is lagging behind in decarbonization
The maritime sector lags behind others, notably road and aviation. There are many reasons, but the main one is that renewing ships and ship engines, which can only burn a certain type of fuel, is a major and expensive decision. Ships are on the water for at least 20 years, often longer. Homeowners consider solutions but struggle to choose. There is a trend in the industry towards a wait-and-see approach.
The trigger for change will be regulation. The cost of fuel is 25% to 40% of the operating cost of a ship. Changing fuel, which can be 50% more expensive, will not be done voluntarily. Shipping is an international business, and you would expect the International Maritime Organization to take the lead in legislating a framework for decarbonizing marine fuels globally. It is done, but it takes a long time.
Meanwhile, Europe proposed the maritime Fuels EU initiative in July 2021. It is part of a set of proposals called Fit for 55, designed to reduce emissions by 55%. Between 2030 and 2050, there will be a radical shift in the use of energy carriers, away from fossil fuels and towards decarbonization. Different types of fuels, which may have the same energy content, will provide significantly different results in terms of greenhouse gas reduction and carbon intensity. By selecting a carbon intensity target, regulators want to reward fuels and energy carriers that reduce emissions rather than simply rewarding renewable fuel content, regardless of greenhouse gas reductions. The trajectory is a reduction of 2% by 2025, 6% by 2030 and 75% by 2050.
Another influence is the companies, including Amazon, Ikea and Unilever, which have committed to using only carbon-free fuel by 2050. When large companies commit to decarbonizing, it has an impact on the whole of their supply chain, including transportation.
What makes a good marine fuel?
There are features that make a low carbon marine fuel, and a handful that stand out are:
- Energy density
- Low carbon intensity
- Ease of use
- Compatibility with current fleet and infrastructure
Biofuels and eFuels, synthetic fuels made from green hydrogen and captured carbon, are good marine fuels. You have natural gas and biomethane in the form of liquefied natural gas (LNG) or bio-LNG, if the methane comes from biogenic feedstocks. Feedstock is any biological material used as fuel or converted into fuel or energy product.
Biomethane/LNG is already proven. Shipowners are converting to LNG or buying new LNG ships. Biomethane is easy to produce and cheap. It is clean and compatible with fossil natural gas. People who equip ships with LNG engines know that they will never run out of fuel. The energy density is not high compared to marine gas oil and fuel oil in place. To keep LNG in liquid form, it must be cooled to low temperatures, which requires bulky cryogenic equipment. Then there is the fleet conversion cost and time. Another problem with biomethane is the risk of leakage. Methane is 30 times more potent than carbon dioxide. A small amount of methane escaping into the atmosphere can have a major impact.
Bio-methanol is already used commercially as a marine fuel. For example, Mærsk has invested a significant amount in methanol vessels. An advantage is the number of ways to produce bio-methanol: for example, from biogenic raw materials, by gasification and reforming of syngas into methanol. You can also produce methanol from green or blue hydrogen with carbon capture. And, of course, there’s fossil, or gray, methanol. You’ll never run out of fuel, and it’s clean burning. Energy density is a drawback, as is conversion cost and time.
Hydrogen and ammonia are grouped together because ammonia converts hydrogen energy into something more easily transportable in liquid form. Green hydrogen, produced by the electrolysis of water with green electricity, could be a long-term solution. It has high sustainability credentials, there is no land use, it is clean burning and there is no competition for raw materials. However, hydrogen is far from commercially available. A key issue is the high cost of electrolysers and green electricity. Converting hydrogen to ammonia improves energy density, but it still does not compare favorably to current fossil fuels. More importantly, handling and safety are an issue: ammonia is highly toxic.
Ultimately, biofuels are the most available and the easiest to integrate. The use of biofuels delays risky decisions and helps maritime organizations kick start decarbonization. Renewable diesel and biodiesel – also called fatty acid methyl ester (FAME) – have been widely tested as replacements for fossil marine gas oil, but the price is higher than the fuel in place.
In the case of FAME and renewable diesel using HVO, another disadvantage is the limitation of raw materials. The raw materials are lipids: fats and oils. Regulators are curbing the use of food crops, such as palm oil, canola oil and soybeans, and pushing for the development of waste oils, such as used cooking oil. However, these are limited resources. Simply put, the world will run out of biofuel eligible lipids for FAME and HVO.
One way to avoid this is to switch to eFuels, which may be the long-term solution. However, the cost is currently prohibitive and production capacity is low. But as a long-term marine application, eFuels in the form of fully compatible e-hydrocarbons resembling very clean diesel or fuel oil would have an advantage over simply using ammonia as a hydrogen energy carrier. .
There are additional possibilities, such as something that would be inferior to HVO renewable diesel but good enough for marine engines. We could well describe bio-methanol, but other solutions come from some of the thermochemical conversion processes that are being developed to deal with other feedstocks beyond lipids – such as biomass, municipal solid waste , recycled carbon and recycled plastics. What about techniques like pyrolysis, hydrothermal liquefaction? Could some of the byproducts of these processes be the perfect marine biofuel?
For example, Mærsk and Vertoro are developing lignin-based biofuels. Lignin is a part of biomass that is difficult to transform; in fact, this is the hardest part to get useful products from. In other developments, UK-based Green Fuels Research recently carried out a pilot project to produce a marine biofuel from salmon farming waste. These experiences and others could be a game-changer if successful.
About Olivier Macé
Olivier Macé is the owner and director of Broadmanor Consulting, a biofuel consultancy. Previously, he worked in the downstream petroleum and biofuels industries for 31 years, holding various positions in refining, trading, supply and logistics, fuels and lubricants sales, and renewable energy. Olivier joined BP Biofuels from its inception and held various management positions, including Regional Director, Europe and Africa and Global Head of Strategy, Regulatory Affairs and Communications. Olivier was Director of Biofuels, Europe Fuels at BP, responsible for the commercial performance of biofuel across the region.
This article on the energy industry was adapted from GLG’s Webcast “Low Carbon Fuels in the Maritime Industry”. If you would like access to events like this or would like to speak with energy industry experts like Olivier Macé or one of our more than 1 million industry experts, please contact us .